Is there any penalty for not changing job?
 

if a level 20 character changes job and then levels to 21, would the hp/sp be the same as someone who changed job at level 21, or would there be any less hp/sp (if both have same builds/items)?

I'm guessing that they stats and stuff should all be the same as someone who has done the job change.

The only penalty is that they can't learn the skills. Right..? -thinks-

Oh and I don't think someone who hasn't done the job change can equip the higher levelled stuff, anyway.

Well but one thing i know is that ur hp and sp increase when u complete the job change... and i was wondering if it matters if i complete the job change 1 level later?

Really? Ohh I never knew that.

I don't think it really matters when you do your job change. Because after completing the quest, your hp/sp should still go up. Just guessing though. x-x

It doesn't change when you level I believe. For instance the mages at level 20, the clone has 4k Hp, if you do it at 25, the clone will still have 4k HP.

There is some minor stat differences because you get a small stat boost upon completing the job change, and you can't equip any new equipment. There's no difference at the job change, even if you level up to 40-something before doing it.